A communication network, such as a switched telephone network, can include a number of interconnected switches that route communications in the network. A call made from one telephone can be routed through several of these switches before reaching the telephone receiving the call. If another call is made between the same two telephones, a different set of switches could be used to route the call.
Communication network users and providers often want to determine exactly which switches and facilities in the network are being used to route a particular communication. Such a capability would trace the path, or route, that a particular communication takes through the network to reveal the origin and destination of that communication, and other pertinent data, such as the specific path that the call utilized.
Knowing which switches and facilities are being used to route a particular call can help a network provider maintain and troubleshoot problems in the network by isolating a particular line or switch that is not functioning as expected. Tracing phone calls can also aid the police or other government authority identify and locate potentially criminal activities.
Another reason for tracing a call is to determine if a call is being received from a particular phone number, even when caller ID is blocked. For example, a network user operating a 1-800 number may wish to keep track of, and reduce, the number of prank phone calls received from the public. A network user might also want to identify the originating location when a caller activates a certain communications service feature, such as the fraudulent entry of a restricted account code, or determine the use of a particular network element such as a particular trunk.
Obviously, in all of the above examples it would be much better to trace a particular communication while the communication is still in-progress. As used herein, the terms "in-progress," "real time" and "interim" in conjunction with a telephone call or associated call record indicate that the associated call has not been terminated, i.e., has not been disconnected. Currently, network users and providers have no easy way to trace the specific route of a particular communication in the network. Instead, tracing is done manually on a switch by switch basis to discover the next switch that sent or received the call. This requires the use of special telecommunications equipment and/or specially trained network provider personnel. The process is time consuming and often cannot trace the route that a particular call takes before the call is terminated.
The method and apparatus disclosed herein takes advantage of the fact that a communications switch stores a variety of information about each call processed by that switch. Existing designs allow a communication switch to include additional information when a signal from, for example, a Network Control Point (NCP) indicates that this should be done for a specific call. This additional information can instruct the communications switch to output the information before the call is terminated. For example, U.S. Pat. No. 5,506,893, issued Apr. 9, 1996, discloses the real time generation of call records in switches for in-progress telephone calls.
In view of the foregoing, it can be appreciated that a substantial need exists for an improved method and apparatus for tracing specific communications using information stored in a communications switch, such as call records.